Tuesday, November 14, 2006

SABR member Alan Nathan who is a Professor of Physics at the University of Illinois has weighed in on the physics of the gyroball. According to many published reports like the CBS news story I linked to a while back, the pitch would have a sharp break away from right-handed hitters when thrown by a right-handed pitcher.

Nathan, however, disagrees and using figures given to him by Dr. Ryutaro Himeno, the Japanese computer scientist who discovered the gyroball, shows that the pitch would much more likely behave like a split-fingered fastball since a "pure gyroball" would have no backspin and therefore no lift as does a regular fastball. It would, however, have a very small amount of break away from a right-handed hitter.

However, Nathan also includes two additional models for gyroballs with slightly different spin axes and these wouldn't have as much downward break because of more backspin but the "gyroball with side force" would behave much like a cut fastball but with more drop. This may be why Al Leiter in the CBS piece said the pitch looked like a cut fastball.